Ultrathin Two-Dimensional ZnIn2S4/Nix-B Heterostructure for High-Performance Photocatalytic Fine Chemical Synthesis and H2 Generation

Photocatalytic H₂ evolution coupled with organic transformation provides a new avenue to cooperatively produce clean fuels and fine chemicals, enabling a more efficient conversion of solar energy. Here, a novel two-dimensional (2D) heterostructure of ultrathin ZnIn₂S₄ nanosheets decorated with amorphous nickel boride (Ni_x-B) is prepared for simultaneous photocatalytic anaerobic H₂ generation and aromatic aldehydes production. This ZnIn₂S₄/Ni_x-B catalyst elaborately combines the ultrathin structure advantage of the ZnIn₂S₄ semiconductor and the cocatalytic function of Ni_x-B. A high H₂ production rate of 8.9 mmol h^-1 g^-1 is delivered over the optimal ZnIn₂S₄/Ni_x-B with a stoichiometric production of benzaldehyde, which is about 22 times higher than ZnIn₂S₄. Especially, the H₂ evolution rate is much higher than the value (2.8 mmol h^-1 g^-1) of the traditional photocatalytic half reaction of H₂ production with triethanolamine as a sacrificial agent. The apparent quantum yield reaches 24% at 420 nm, representing an advanced photocatalyst system. Moreover, compared with traditional sulfide, hydroxide, and even noble metal modified ZnIn₂S₄/M counterparts (M = NiS, Ni(OH)₂, Pt), the ZnIn₂S₄/Ni_x-B also maintains markedly higher photocatalytic activity, showing a highly efficient and economical advantage of the Ni_x-B cocatalyst. This work sheds light on the exploration of 2D ultrathin semiconductors decorated with novel transition metal boride cocatalyst for efficient photocatalytic organic transformation integrated with solar fuel production.